A gun weighing 1000 kg recoils with a velocity of 3 × 10-2 m/s when a

1.	A gun weighing 1000 kg recoils with a velocity of 3 × 10-2 m/s when a shell of mass 1 kg is shot from it. If the shell hits the target in 8 seconds, find the gun target distance.
Answer» Initial momentum of the gun & that of shell is zero as they are at rest. Recoil velocity of the gun v₁ = – 3 × 10^-2ms^-1 Mass of the gun m₁ = 1000kg Mass of the shell m₂ = 1 kg velocity of the shell v₂ =? From the equation m₁ u₁ + m₂ u₂ = m₁v₁ + m₂ v₂ 0 = 1000(- 3 × 10^-2 ) + 1 .v² ∴ v₂ = 30ms^-1 The gun target distance, s = v₂ × t = 30 × 8 = 240m.

A gun weighing 1000 kg recoils with a velocity of 3 × 10-2 m/s when a shell of mass 1 kg is shot from it. If the shell hits the target in 8 seconds, find the gun target distance.

Answer»

Initial momentum of the gun & that of shell is zero as they are at rest.

Recoil velocity of the gun v₁ = – 3 × 10^-2ms^-1

Mass of the gun m₁ = 1000kg

Mass of the shell m₂ = 1 kg

velocity of the shell v₂ =?

From the equation

m₁ u₁ + m₂ u₂ = m₁v₁ + m₂ v₂

0 = 1000(- 3 × 10^-2 ) + 1 .v²

∴ v₂ = 30ms^-1

The gun target distance,

s = v₂ × t

= 30 × 8

= 240m.